System for and method of controlling a light source and lighting arrangement

ABSTRACT

The invention relates to a system for controlling a light source ( 208, 210, 212 ) within an area ( 200 ), the system comprising: location means conceived to detect a position of at least one person within an area ( 200 ); activity means conceived to detect a kind of activity performed by the at least one person within the area; and lighting control means conceived to control the light source ( 208, 210, 212 ) within the area ( 200 ) in response to the detected at least one person and the kind of activity performed by the at least one person within the area ( 200 ).

The invention relates to a system for controlling a light source withinan area.

The invention further relates to a method of controlling a light sourcewithin an area.

The invention further relates to a lighting arrangement comprising sucha system.

An embodiment of such a system and method is disclosed in U.S.2002/0015097. Here, a lighting arrangement is described that comprises asensor which is capable of measuring electromagnetic radiation,preferably visible light as well as infrared light, in a room. Thelighting arrangement further comprises control means for controlling thelighting in the room in dependence upon the measured radiation. Thesensor comprises a video sensor, such as a Charged Coupled Device (CCD)sensor, which is capable of producing an electronic image of the room.With this lighting arrangement switching a light source on or off iscontrolled automatically in dependence on the presence of people. If oneor more persons are detected in for example an office, the light sourceis switched on as long as the person is present within the office.Further, clock information can be used to, depending upon the time ofday, switch-on all lights for example for a cleaning service, orswitch-on only the orientation lighting so that people can find theirway to the workplace. With this lighting arrangement there is limitedcontrol of the lighting in a room.

It is an object of the invention to provide a system according to theopening paragraph that controls a light source in an improved way. Toachieve this object, the system for controlling a light source within anarea comprises location means conceived to detect a position of at leastone person within an area; activity means conceived to detect a kind ofactivity performed by the at least one person within the area; andlighting control means conceived to control the light source within thearea in response to the detected at least one person and the kind ofactivity performed by the at least one person within the area. Bydetecting the activity that a person is performing, the most suitablelight source for that activity can be supplied to the person. Forexample, when a person is reading a book the light source should bebrighter than when a person is watching a television program. The lightsource can also be focussed upon the book in the case that the person isreading, while the light source should not be focussed upon thetelevision screen in the case that the person is watching a televisionprogram. In the latter case indirect light via for example the ceilingis more appropriate. As a further advantage, a person does not have tocontrol the light source by explicitly operating the light switch inorder to change the light settings for a specific activity.

An embodiment of the system according to the invention is described inclaim 2, wherein the system comprises intensity means conceived todetect an intensity with which the kind of activity is performed by theat least one person and the lighting control means is conceived tocontrol the light source within the area in response to the detectedintensity. The intensity can depend upon the kind of activity. Forexample, when a person is operating a personal computer and interactswith a word processing program the intensity of interaction with thisword processing program is different from the intensity of interactionwith for example a car-racing game. Depending upon this intensity, thelights are adjusted accordingly. For the word processing program thiscan result in white or yellow light with an average brightness level,while for the car-racing game, the lights can change continuously fromcolor with a varying brightness level.

An embodiment of the system according to the invention is described inclaim 3, wherein the system comprises dating means conceived todetermine a date and a time and the lighting control means is conceivedto control the light source within the area in response to thedetermined date and time. The brightness level can depend upon the timeof day that an activity is being performed. For example, duringbreakfast in the morning people prefer brighter lights while eating thanduring dinner in the evening.

An embodiment of the system according to the invention is described inclaim 4, wherein the system comprises noise means conceived to detectnoise within the area and the lighting control means is conceived tocontrol the light source within the area in response to the detectednoise. By detecting the noise it can be detected if someone is presentin a room and the lights should be switched on. Furthermore, theintensity of a conversation between two persons can be detected. Forexample, when two persons are talking to each other in a relaxed manner,the lighting remains at a dimmed level. However, if their conversationbecomes more intense because the volume goes up, the lighting brightens.

An embodiment of the system according to the invention is described inclaim 5, wherein the system further comprises motion means conceived todetect motion of the person within the area and the lighting controlmeans is conceived to control the light source within the area inresponse to the detected motion. In the case that the person walksaround the room, the person needs more light to properly see where he orshe is walking. In the case that the person sits in a chair the lightsource can become less bright. This way, the lights can be controlledbetter.

An embodiment of the system according to the invention is described inclaim 6, wherein the system further comprises preference means conceivedto determine a preference of a person and the lighting control means isconceived to control the light source within the area in response to thepreference of the at least one person. Different persons can havedifferent preferred lighting settings. For example, an older person canprefer a more bright light for reading than a younger person can,because the eyes of an older person are less sensitive to light. Alsopreferences depending upon personal taste like the color of light thatis preferred can be taken into account while controlling the light.

It is an object of the invention to provide a method according to theopening paragraph that controls a light source in an improved way. Toachieve this object, the method comprises detecting a position of atleast one person within an area; detecting a kind of activity performedby the at least one person within the area; and controlling the lightsource within the area in response to the detected at least one personand the kind of activity performed by the at least one person within thearea.

Embodiments of the method according to the invention are described inclaim 7 and 8.

It is an object of the invention to provide a lighting arrangementaccording to the opening paragraph that controls a light source in animproved way. To achieve this object, the lighting arrangement comprisesthe system according to any of the claims 1 to 6.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiments described hereinafter asillustrated by the following Figures:

FIG. 1 illustrates an adaptive light environment according to theinvention in a schematic way;

FIG. 2 illustrates a room with an adaptive light environment in aschematic way;

FIG. 3 illustrates a room setting with multiple light settings in aschematic way;

FIG. 4 illustrates a system according to the invention in a schematicway;

FIG. 5 illustrates a method according to the invention in a schematicway;

FIG. 6 illustrates a lighting arrangement according to the invention ina schematic way.

Nowadays, light is becoming more and more important to illuminate roomswhere people spend their time. The lighting conditions depend upon anumber of factors like the natural light that penetrates an office, thetime of the day, the environment. As an example, lighting conditionsthat are considered by most individuals as extremely uncomfortable in anoffice environment might be positively welcomed in a discotheque.Several aspects of lighting can be manipulated: the amount of light, thedistribution of light, the spectrum of the light, the variation of theseaspects over time, and the appearance of the luminaire.

The illuminance is the amount of light falling onto a surface. Theamount of illumination required to be able to perform a task like forexample reading at a comfortable level differs from what is required fora task like for example fine needlework. For example, illuminancerequired for optimum visibility for medium contrast paper-based tasksranges from 500 to 1000 lux, which is considerably higher than forcomputer screen visibility.

Luminance is the amount of light emitted by a surface. Luminance levelsin a room usually vary because of the different objects that are presentwithin the room. A luminance ration of 10:3:1 between the task to thesurrounding area to the general back ground is generally found to becomfortable.

Glare occurs when there are areas of high brightness in the visual fieldof a person. Direct glare is caused by light sources in the field ofview, reflected glare is caused by reflections of high brightness fromfor example glossy surfaces. Glare can cause discomfort by reducing theability to see fine details. Glare can be reduced by using indirectlighting.

Reflectance of walls, ceilings and other surfaces in a room, influencethe distribution of light in a room.

The lighting conditions are also determined by the colors that are used.The appearance of any color is determined by the hue, saturation, andlightness. The hue is the quality by which a color is distinguished fromother colors. Saturation is also referred to as strength, intensity orchroma; it designates the purity of a given color. Lightness of a coloris a measure of how much light is reflected from its surface.

When designing an adaptive light system all these different aspects canbe taken into account in order to create a light system that adapts thelight appropriately.

FIG. 1 illustrates an adaptive light environment according to theinvention in a schematic way. A personal computer (PC) 102 is connectedto light units 104, 108, and 110 and to sensor unit 106. This network ofappliances is connected through Ethernet connection and the light unitsare controlled through a Local Operating Network (LON) controllerrunning at the PC 102. The light units can also be controlled by using aDigital Addressable Lighting Interface (DALI) or by a proprietarymicro-controller printed circuit board (PCB) that can directly controlthe light unit's ballast. The light unit 104 is a halogen lamp. Lightunit 108 comprises two lamps: one warm light incandescent lamp and onecold light incandescent lamp. Light unit 110 comprises a Light EmittingDiode (LED) array that comprises a Red, Green and Blue LED. The halogenlamp offers functional lighting by varying the spot size and intensitythrough dimming. The warm and cold light provide the ambiance. Ingeneral, every color has its specific properties that can evoke specificemotions. Red and orange are generally assumed to suggest “warmth andcoziness”, and blue is considered to suggest “cool and cheerless” whilea wild mixture of colors suggests “cheerful and festive” and purple andblack are assumed to evoke a “sad and somber” atmosphere. Some othercolors are assigned specific associations, like green is rest and whiteis sterile. Therefore, the warm light provides red and orange colorswhile the cold light provides blue and white colors. With the LEDscolors can be blended by optically blending the lights of the Red, Greenand Blue LEDs. The sensor unit 106 comprises a motion sensor to detectmovement within an area. The sensor unit 106 can also comprise a videocamera that can record objects like persons, tables, and animals thatare present within a room. The sensor unit 106 can further comprise amicrophone through which the noise level can be recorded.

The number and kind of light units that are used merely act as anexample this hold also for the connection used for connecting allappliances with the PC.

FIG. 2 illustrates a room with an adaptive light environment in aschematic way. The room 200 comprises a table 202, two chairs 204, alighting arrangement 206 and three light sources 208, 210, and 212mounted on the lighting arrangement 206. A video surveillance camera 214is mounted in a corner of the room. In another corner, a microphone 216is mounted to the ceiling. The lighting arrangement 206, videosurveillance camera 214 and microphone 216 are connected to the LONcontrol PC 102 as described in connection with FIG. 1. The light sources208, 210 and 212 are halogen lamps of which the luminance level andfocus can be controlled.

With these settings the following use case can be performed: Today Petehas decided to take an easy start. After a long shower he goes to thekitchen to make coffee. With the morning paper in one hand and thecoffee in the other he enters the living room. Upon entering the livingroom, the video surveillance camera starts recording and the videoimages are continuously sent to the PC. On the PC a dedicated softwaremodule that is designed to analyze the video starts running to analyzethe video. From this analysis the software module derives that there ismovement detected in the living room. The detection software modulepasses this information to a light controlling module which is alsorunning on the PC. The light controlling module is designed to controlthe light settings of the light sources 208, 210 and 212. Upon receiptof the message that movement is detected in the living room, the lightcontrolling module causes each halogen light to be switched on into amoderate luminance level and with a wide focus. This way, Pete caneasily walk across the room and positions himself at the long table. Hedrinks his coffee and folds open the morning paper. Now the detectionsoftware module derives from the analysis of the video that a person(Peter) is sitting near the table and that an object (the morning paper)lies in front of the person. This information is passed to the lightcontrolling module. Instead of analyzing the video images, the chairsand table can also comprise pressure sensors. Then from the datareceived from the pressure sensors, the detection software module canderive that a person is sitting on a chair and that an object lies onthe table. The light controlling module causes the halogen lamps tofocus onto Pete's position and the luminance level is raised. Somemoments later, Jana enters the room and positions herself at the tableopposite of Pete. She starts discussing their holiday plans. Themicrophone 216 detects the sound of their voices. This sound iscontinuously sent to the PC. On the PC, another software module isrunning that is designed to analyze noise signals. The noise analyzingsoftware module gives a signal to the light controlling module thatthere is noise detected in the room. Upon receipt of this signal, thelight controlling module decreases the intensity of the halogen lampsagain. Meanwhile the video analyzing module has analyzed that an otherperson is sitting opposite of the first person and transfers thisinformation to the light controlling module. The information cancomprise the coordinates of the two persons as absolute coordinateswithin the room or as relative to the halogen lights. Upon receipt ofthis information, the light cone is widened again to include both Peteand Jana into the light focus.

Within an other use case, Pete is working at home. He sets himself atthe table with his laptop in front of him. It is being detected that alaptop is at the table using the video as previously described. Thiscauses the lighting to be focussed at and around Pete and his laptopwith a luminance level adjusted for the laptop's screen. The laptop isalso connected to a home network that is again connected to the LONcontrol PC. Pete starts using a text processing program. Thisinformation is transferred to the LON control PC. The light is adjustedto give enough light for Pete to use the text processing program. Now,Pete switches to a graphical program. Since this program requires moreprecise selection of the items presented on the screen, the lightsurrounding the screen is set brighter than in the case of the textprocessing program. After operating the graphical program, Pete has tocontact one of his clients. He starts a videoconference program. Againthis information is sent to the light controlling software module. Now,the light fades again into a warm atmosphere, to make the client feel atease.

FIG. 3 illustrates a room setting with multiple light settings in aschematic way. The room 300, comprises a dining area I that comprises atable 302 above which two light sources 304 are mounted. Four chairs 306surround the table 302. The room also comprises a television area IIIthat comprises a television 310, a light source 312 and a couch 308.Further, the room 300 comprises a relaxing area II that comprises achair 314 and a light source 316. A video camera 318 is mounted againstthe ceiling. The room is divided into three areas I, II and III. Withineach area the light settings can be controlled separately. Within thesoftware module that is designed to analyze the video content, thecoordinates of each area are known. Now, when a person enters the room,the coordinates where the person is determines the lights that arecontrolled. For example, when there's only one person in the room who issitting in chair 314, only light source 316 is switched on by the lightcontroller software module. Depending upon the activity of the person,the light settings are adjusted. If the person is performing needle workthe light is for example brighter than if the person is reading a book.In the case that there are multiple persons present that are eachlocated into a different area of the room, more lights are controlled.For example, when one person is reading a book at the dining table 302,the lights 304 are switched on and focussed onto the person with thebook. If another person is watching television 310, the light 312 nextto the television 310 is switched on and directed to the ceiling toprovide indirect light onto the television 310.

FIG. 4 illustrates a system according to the invention in a schematicway. The system 400 comprises a central processing unit 402, a randomaccess memory 410, a software bus 428 and an ethernet connection 408.The ethernet connection 408 connects the system to appliances like lightsources, video camera, microphone etc. The memory 410 can communicatewith the central processing unit 402 via software bus 428. The memory410 comprises computer readable code 412, 414, 416, 418, 420, 422, 424,and 426. The computer readable code 412 is designed to deduce a locationof a person inside an area. The location can be deduced from video. Thelocation can further be deduced from pressure sensors that are locatedwithin the area or by other appliances that are known in the art like aIR sensor or a proximity sensor. The computer readable code 414 isdesigned to deduce the activity that a person is performing within thearea. The activity can be deduced from an explicit message that is beingreceived via ethernet connection 408 from a connected appliance. Forexample, a PC can supply a message indicating the application that aperson is using, or a coffee machine can supply a message indicatingthat the coffee machine is being used by the person. Other activitiescan for example be: reading, listening to radio, sleeping, talking onthe telephone, watching a movie, talking, etc. The computer readablecode 418 is designed to determine the intensity with which the activityis being performed. The intensity can for example be deduced from thenumber of keystrokes a person uses to provide input to a PC. Theintensity can also be deduced from the noise level: the higher the noiselevel of a conversation, the more intense the conversation is. Thecomputer readable code 420 is designed to determine the date and time.The date and time can influence the light settings. The light settingscan depend upon the time: morning, evening and the date: weekend,weekdays, daylight saving time, etc. The computer readable code 422 isdesigned to detect the noise level inside the area. It can determine theamount of decibels that are being produced by the persons inside thearea. The sound is provided through a microphone that is connected tothe ethernet connection 408. The computer readable code 424 is designedto determine if there is motion being detected inside the room. A motiondetector is therefore connected to the system 400. The computer readablecode 426 is designed to comprise the preferences concerning lightsettings of the different persons that can enter the area. Thepreferences can be used in combination with the readings from computerreadable code 412 and 422. Hereto, the computer readable code 412 isfurther designed to detect the person that is present inside the area.It can recognize, by analyzing the video images and performing facerecognition, the person and/or persons that are present. Further, thecomputer readable code 422 is further designed to recognize the personsfrom their voice prints. By combining these preferences, specificpreferences are taken into account like preferred light colors orluminance levels. Also, non-specific preferences can be taken intoaccount like the age of the persons. Computer readable code 416 isdesigned to transfer the specific lighting settings to the lights thatare connected to the system through ethernet connection 408. Theresponsibility of translating the readings from the connected sensorsinto light settings can lay with the specific computer readable codethat receives the readings, or is can lay within the computer readablecode 416 that transfers and directs the specific lighting settings. Thisis a matter of design. The system is described by means of example as asoftware system. However, dedicated hardware or combinations of softwarewith hardware, like programmable hardware is also possible.

FIG. 5 illustrates a method according to the invention in a schematicway. Step 500 is an initialization step within which each sensorregisters itself with the LON control PC. Further, the settings andcapabilities of the light sources that are used are transferred to theLON control PC. Within the next step S502, the location of a personwithin the room is determined. For example, by determining thecoordinates of the position within an area within the room. Within stepS504, the activity that the person is performing is determined. Withinstep S506, the intensity with which this activity is being performed isdetermined and within step S508, the current date and time are beingdetermined. Within the next step S510 the noise level that is beingproduced inside the room is being detected. It is also possible todetermine the location where the noise level is highest. Within stepS512, motion within the different areas within the room is beingdetected and within step S514, the user preferences are being taken intoaccount such that all of this information can be translated within stepS516 into the most suitable lighting settings like hue, saturation,color, direction, focus, etc. The method stops within S518. Dependingupon the appliances that provide information for the different steps aspreviously described, steps can be omitted or the sequence of steps canbe changed.

FIG. 6 illustrates a lighting arrangement comprising a system accordingto the invention. The lighting arrangement 600 comprises three LEDlights: 602, 604, and 606 each of a different color: red, green, andblue. The lighting arrangement further comprises the system 608according to the invention as previously described. The lightingarrangement can be connected through the ethernet connection provided bythe system 608 to other lighting arrangements and also to sensors.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. In the claims, any reference signsplaced between parentheses shall not be construed as limiting the claim.The word “comprising” does not exclude the presence of elements or stepsother than those listed in a claim. The word “a” or “an” preceding anelement does not exclude the presence of a plurality of such elements.The invention can be implemented by means of hardware comprising severaldistinct elements, and by means of a suitably programmed computer. Inthe system claims enumerating several means, several of these means canbe embodied by one and the same item of computer readable software orhardware. The mere fact that certain measures are recited in mutuallydifferent dependent claims does not indicate that a combination of thesemeasures cannot be used to advantage.

1. System for controlling a light source within an area, the system comprising: location means conceived to detect a position of at least one person within an area; activity means conceived to detect a kind of activity performed by the at least one person within the area; and lighting control means conceived to control the light source within the area in response to the detected at least one person and the kind of activity performed by the at least one person within the area.
 2. System according to claim 1, the system comprising intensity means conceived to detect an intensity with which the kind of activity is performed by the at least one person and the lighting control means is conceived to control the light source within the area in response to the detected intensity.
 3. System according to claim 1, the system comprising dating means conceived to determine a date and a time and the lighting control means is conceived to control the light source within the area in response to the determined date and time.
 4. System according to claim 1, the system comprising noise means conceived to detect noise within the area and the lighting control means is conceived to control the light source within the area in response to the detected noise.
 5. System according to claim 1, the system comprising motion means is conceived to detect motion of the person within the area and the lighting control means is conceived to control the light source within the area in response to the detected motion.
 6. System according to claim 1, the system comprising preference means conceived to determine a preference of a person and the lighting control means is conceived to control the light source within the area in response to the preference of the at least one person.
 7. Method of controlling a light source within an area, the method comprising: detecting a position of at least one person within an area; detecting a kind of activity performed by the at least one person within the area; and controlling the light source within the area in response to the detected at least one person and the kind of activity performed by the at least one person within the area.
 8. Method according to claim 7, the method comprising detecting an intensity with which the kind of activity is performed by the at least one person and the step of controlling the light source comprises controlling the light source within the area in response to the detected intensity.
 9. Lighting arrangement comprising the system according to claim
 1. 